A masked gunman who opened fire in the crowded Clackamas Town Center mall in suburban Portland, Ore., killing two individuals and seriously injuring a third before killing himself, has been identified by police, though they have not yet released his name.

The shooter, wearing a white hockey mask, black clothing, and a bullet proof vest, tore through the mall around 3:30 p.m. Tuesday, entering through a Macy's store and proceeding to the food court and public areas spraying bullets, according to witness reports.

"We have been able to identify the shooter over last night," Sheriff Craig Roberts told "Good Morning America" today.
"At this point in time, because of the investigation, we're actually doing supplemental search warrants, we're not able to release the name of the individual at point in time for the reason being that we don't want to jeopardize the investigation."

Police have not released the names of the two deceased. Clackamas County Sheriff's Department Lt. James Rhodes said authorities are in the process of notifying victims' families.

The injured victim has been transported to a local hospital, according to Clackamas County Sheriff Craig Roberts.

Nadia Telguz, who said she was a friend of the injured victim, told ABC News affiliate KATU-TV in Portland that the woman was expected to recover.

"My friend's sister got shot," Teleguz told KATU. "She's on her way to (Oregon Health and Science University hospital). They're saying she got shot in her side and so it's not life-threatening, so she'll be OK."

Witnesses from the shooting rampage said that a young man who appeared to be a teenager ran through the upper level of Macy's to the mall food court, firing multiple shots, one right after the other, with what is believed to be a black, semi-automatic rifle.

More than 10,000 shoppers were at the mall during the day, police said. Roberts said that officers responded to the scene of the shooting within minutes, and four SWAT teams swept the 1.4 million-square-foot building searching for the shooter. He was eventually found dead, an apparent suicide.

"I can confirm the shooter is dead of an apparent self-inflicted gunshot wound," Rhodes said. "By all accounts there were no rounds fired by law enforcement today in the mall."

Roberts said more than 100 law enforcement officers responded to the shooting, and at least four local agencies were working on the investigation, including the FBI and Bureau of Alcohol, Tobacco and Firearms, which is working to trace the shooter's weapon.

"For all of us, the mall is supposed to be a place where we can take our families, especially during the holiday season," Roberts said. "Things like this are not supposed to happen."

Roberts also said that shoppers, including two emergency room nurses and one physician who happened to be at the mall, provided medical assistance to victims who had been shot. Other shoppers helped escort individuals out of the mall and out of harm's way, he said.

"There were a huge amount of people running in different directions, and it was chaos for a lot of citizens, but true heroes were stepping up in this time of high stress," Roberts said. "E.R. nurses on the scene were providing medical care to those injured, a physician on the scene was helping provide care to the wounded."

Mall shopper Daniel Martinez told KATU that he had just sat down at a Jamba Juice inside the mall when he heard rapid gunfire. He turned and saw the masked gunman, dressed in all black, about 10 feet away from him.

"I just saw him (the gunman) and thought, 'I need to go somewhere,'" Martinez said. "It was so fast, and at that time, everyone was moving around."

Martinez said he ran to the nearest clothing store. As he ran, he motioned for another woman to follow; several others ran to the store as well, hiding in a fitting room. They stayed there for an hour and a half until SWAT teams told them it was safe to leave the mall.

Witness Amber Tate said she was in the parking lot of the mall when she saw the shooter run by, wearing a mask and carrying a machine gun, headed for the Macy's.

"He looked like a teenager wearing a gun, like a bullet proof vest and he had a machine, like an assault rifle and a white mask and he looked at me," she said.

Other witnesses described the shooter as being on a mission and determined, looking straight ahead. He then seemed to walk through the mall toward the other end of the building, shooting along the way, according to witness reports.

Witnesses told KATU they heard "pops" and then saw the mall Santa fall to the ground. The man dressed as Santa, who did not give his name, told KATU that he wasn't concerned at first by what sounded like balloons popping.

"Then when I heard about 18 more shots, I decided it was a semi-automatic and I hit the floor and my employees must have just scattered and got out of there because when I got up there was nobody there but me," he said.

Others interviewed said that Macy's shoppers and store employees huddled in a dressing room to avoid being found.

"I was helping a customer in the middle of the store, her and her granddaughter and while we were looking at sweatshirts we heard five to seven shots from a machine gun fire just outside my store," Jacob Rogers, a store clerk, told KATU.

"We moved everyone into the back room where there's no access to outside but where there's a camera so we can monitor what's going on out front," Rogers said.

Evan Walters, an employee of a store in the mall, told ABC News Radio that he was locked in a store for his safety and he saw two people shot and heard multiple gunshots.

"It was over 20, and it was kind of surreal because we hear pops and loud noises," he said. "We're next to the food court here and we hear pops and loud noises all the time, but we don't -- nothing like that. It was very definite gunshots."

Former FBI agent and ABC News contributor Brad Garrett said the shooter's mask is typical for mass shooters, who often dress up in costume or wear something other than their regular clothes when they open fire in public.

"The biggest thing for a mass shooter is the control and empowerment for the shooting," he said. "It isn't uncommon for shooter to wear a costume, or sometimes simply to dress in black. In this case, apparently, he wore a hockey mask. He went there being someone other than who he is in reality because it gives him power."

Garrett called the shooting today one of the worst scenarios for law enforcement, as malls are more crowded than ever during the holiday shopping season.

"The thing about mass shooters is that they almost always are premeditated. They are planned," Garrett said. "This shooter I'm sure went through some period of steps before he actually reached going to mall, and there'll be signs or systems either through friends, online, through relatives that will play into understanding why he committed this act."